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Posts tagged #cassandra

2 posts

Build logNov 11, 2026

Building a distributed job scheduler without a queue

at and cron as a service, in Go: six services, MySQL as the queue, Cassandra for history. The decisions behind it, their trade-offs, and what load-testing it on an AWS-shaped bench found, including a bug of mine.

onSystem Design posts Database Internals posts Go posts

#mysql
#cassandra
#scheduling
#distributed-systems
#benchmarks

11 min read · Part 1 of Building a distributed job scheduler

Build logNov 11, 2026

Distributed job scheduler: the design decisions in depth

Why the jobs table is the queue, why MySQL and not Postgres, why Cassandra only for history, and how leases, fencing tokens and idempotency keys keep at-least-once honest. With the alternatives I rejected and the SQL behind each decision.

onSystem Design posts Database Internals posts Go posts

#mysql
#cassandra
#scheduling
#idempotency
#ssrf

12 min read · Part 2 of Building a distributed job scheduler